In a Michelson interferometer, a moving mirror, moving in a linear motion perpendicular to the mirror's plane, is used to cause constructive and destructive interference between two beams derived from a common source. This function of the Michelson interferometer is used in Fourier transform infrared spectroscopy to uniquely identify gaseous molecules by their radiation absorption patterns. The moving mirror of the interferometer modulates the amplitudes of frequencies in a bandwidth of radiation. This resulting radiation is then used to irradiate the target gas to be analyzed. The power of the incident radiation upon the target gas is compared to that power after absorbtion by the gas to determine which frequencies are absorbed.
The moving mirror in the interferometer must be parallel to a fixed mirror in the interferometer to obtain a predictable interference pattern. The usual method of supporting the moving parallel mirror in a Michelson interferometer is with an air bearing. Air bearings are expensive, require the consumption of dry nitrogen, and permit a degree of wobble to the mirror. There are other methods which use "porch swing" flexures with pivots, but these too permit a degree of wobble.
The present invention permits substantially less tilt and wobble than the prior art, thus providing more accurate measurements using an interferometer.